The present invention relates in general to an axial compliance mechanism of a scroll compressor, and more particularly, to a structure for improving axial sealing compliance of a scroll.
A typical scroll compressor includes two scroll members, namely, a fixed scroll and an orbiting scroll. The orbiting scroll revolves about the fixed scroll. In compression operation, the fixed scroll and the orbiting scroll each has an involute wrap inter-fitting each other to allow working fluid entering a compression chamber through a suction port thereof. The continuous revolutions of the orbiting scroll further provide compression of the working fluid until the working fluid is discharged from an inner discharge port of the fixed scroll to complete the compression process of the working fluid. During the compression operation, the volume of the working fluid is reduced, while the pressure thereof is increased. Thereby, axial force, radial force and tangential force are created. The axial force tends to cause axial separation of these two scroll members. The radial and tangential forces generate biasing torques. The axial, radial and tangential forces cause leakage from the end panels or the side surfaces of the wraps. How to enhance the volume efficiency of the compressor has thus become an important topic in this field.
In U.S. Pat. No. 5,256,044, the pressurized working fluid is guided at the back surface of the orbiting scroll member to closely attach the orbiting scroll member to the fixed scroll member, so as to achieve an axial sealing effect. However, as the orbiting scroll member has to overcome the axial force and the biasing torques, an excessive pressure is typically resulted to cause unwanted frictional damage. The lifetime of the compressor is thus greatly reduced.
In the Taiwanese Patent No. 263024, a compressor having a top shell, bottom shell, a fixed scroll, a orbiting scroll and a spacer is disclosed. Each of the top and bottom shells has a cavity. The top shell has a venting hole formed on one side thereof. The top shell is soldered or welded on top of the bottom shell. The bottom shell includes the fixed scroll and the orbiting scroll each having an involute wrap inter-fitting each other. The top surface of the fixed scroll includes a protruding tubular neck. A spacer is firmly installed in the top shell. The center of the spacer is opened with a hole allowing the tubular neck of the fixed scroll to extend through. A plurality of through holes is formed at an adequate distance to the hole of the spacer. The through holes provide connections of various pressure supply devices. Thereby, an axial compliance mechanism of a scroll compressor is formed.
However, as the spacer is fixed in the top shell, and the fixed and orbiting scrolls are fixed in the bottom shell, lateral force and deformation are inevitable during the welding process. As the concentric requirement between the hole of the spacer, the tubular neck of the fixed scroll and the rotation part of the motor is rather high, the yield is typically low. Further, to stably maintain the pressure balance of the spacer, the pressure supply devices and related members have to be spaced by 120° with each other. When many devices are required by the compressor, this greatly increases material and fabrication cost. In addition, when the working fluid is discharged from the venting port of the top shell, the pressure applied to the pressurizing members is uneven to cause unbalance by the fixed scroll, such that high noise and friction between devices are generated.